Liquid fuel heaters



. Feb. 28, 1967 B. T. D. MARTIN LIQUID FUEL HEATERS I Original F'iled Aug. 21, 1962 3 Sheets-Sheet 1 INVENTOR Emmi km DAVID mnefw ATTORNEY Feb. 28, 1967 5.1-. D. MARTIN LIQUID FUEL HEATERS 3 Sheets-Sheet 2 Original Filed Aug. 21, 1962 INVENTOR n wlb In er-w izwmbworms /I!7u a-,ims7m QWAM; @goRNEY Feb. 28, 1967 Original Filed Aug. 21, 1962 B. T. D. MARTIN 3,306,337

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INVENTOR EEBNHBD-ITIOIWHS DAVID lYlnm-w ATTO NEY United States Patent Oflflce 3,306,337 LIQUID FUEL HEATERS Bernard Thomas David Martin, Rettendon, Essex, England, assignor to Maywick Appliances'Limited, Wickford, England, a British company Original application Aug. 21, I962, Ser. No. 218,298, new Patent No. 3,258,056, dated June 28, 1966. Divided and this application Jan. 17, 1966, Ser. No. 521,022 4 Claims. (Cl. 158-81) This application is a divisional of my application S.N. 218,298, filed August 21, 1962, now United States Patent No. 3,258,056.

The invention relates to liquid fuel heaters and particularly to heaters using liquid fuels such as kerosene.

In such heaters ancillary equipment is generally required to pre-heat the burner of the heater and in operation a compressor or the equivalent is normally required to maintain the sup-ply of liquid fuel to the burner.

It is a disadvantage that pre-heating requires either means for supplying a readily combustible substance as, for example, a liquid fuel such as methylated spirit, or else a carrier to enable some of the liquid fuel used in the operation of the burner to be ignited around the burner. Thus, for example, cloth or waste soaked in kerosene is frequently used to effect the pre-heating of a kerosene heater.

It is a further disadvantage of such pre-heating means that carbon deposits are formed which may block the jets of'the burner nozzle and either lessen the efliciency of the heater or renderv it inoperative.

The provision of a compressor or the equivalent to maintain the supply of fuel during operation adds to the cost of the apparatus.

It is among the objects of the invention to overcome these disadvantages.

According to the invention, means are provided in a heater whereby a liquid fuel, such as kerosene, ca able of combustion under pressure or by forced draught, is initially pre-heated andthen pressurised by a combustible gas such as a liquid petroleum gas.

Thus, for example, in application to a heater using kerosene, the pre-heating of a the liquid fuel may be effected by heating the burner nozzle by combustion of propane, supplied under pressure from a container of the gas in liquefied form, the pressure of uncombusted propane in the container being effective, after the pre-heating is completed, to maintain a supply of kerosene to the burner nozzle for vapourisation and combustion.

Furthermore in a heater according to the invention, valve means may be provided for'the simultaneous supply with the liquid fuel of a combustible gas such as propane for heating the nozzle of the burner to maintain the flame burning. Additionally, there may be provided in accordance with the invention control means, advantageously thermostatic control means, automatically operable to increase the supply of the combustible gas should the flame die down.

It is a further feature of the invention that the supply of the gas may be maintained throughout operation to ensure that there is no flame failure or deposit on the burner elements through cracking of the gas.

To effect improved combustion of the liquid fuel during operation of the heater the liquid fuel may be fed to a closed circuit in the burner of the heater so that the heat from the burner heats the liquid fuel during its passage through the closed circuit to the burner nozzle.

An initial pre-heating of the burner is effected by burning at or adjacent to the burner nozzle a combustible gas led from a container of the gas under pressure, after which initial pre-heating the supply of gas is turned off, reduced, or switched to pilot control, the pressure of 3,306,337 Patented Feb. 28, 1967 the combustible gas still in the container being utilised to force the liquid fuel through the liquid flow line to a jet or jets in the burner.

It will be appreciated that by heating the liquid fuel as it passes through the burner head vaporisation and combustion is improved.

Thus according to the invention a burner for the heater may be formed with a head having a gas jet or nozzle and a liquid fuel jet or nozzle, the combustible gas being first ignited at the gas burner nozzle to provide a flame which effects pre-heating of the liquid fuel nozzle, that the liquid fuel after combustion has started is readily ignited and, being led through the head or coil of the burner is heated before reaching the liquid fuel burner nozzle.

According to the invention furthermore there are provided in a heater means for stabilising the flame from the liquid fuel burner nozzle, means for regulating the supply of air to the burner, and filter means in the liquid fuel jet or jets.

Thus the means for stabilising the flame from the liquid fuel burner may comprise a tubular member disposed substantially in the plane of the flame from the burner and inclined to the directions of the flame so as to deflect, direct and concentrate the flame on that part of the burner where maximum heat is required.

In application of the method according to the invention to a space heater means are provided for effecting concentration of the heat from the burner of the heater intoa combustion chamber as, for example, a tubular member from which heat is passed by convection through an annular space surrounding the chamber from which space it passes to atmosphere through a surrounding guard or grid formed of wire mesh or the like.

Alternatively the heat from the burner or burners of the heater may be caused to pass through a perforated part of the wall of the combustion chamber, so that the perforated part becomes incandescent and heating is effected both by radiation and by convection. Advantageously heat passing from the combustion chamber to atmos here may be entrained with air driven through the annular space around the combustion chamber by fan means.

The invention is illustrated by way of example in the accom anying diagrammatic drawings in which:

FIGURE 1 is a schematic diagram illustrating the layout and the gaseous and liquid fuel circuits used in operation of the invention;

FIGURE 2 is a pers ective view of a burner used in operation of the invention the burner head incorporating a coil and stabiliser;

FIGURE 3 is a plan from above of the burner head shown in FIGURE 2;

FIGURE 4 is a sectional view of a burner and stabiliser used in operation of the invention the burner head being form d by plates disposed in spaced relation; and

FIGURE 5 illustrates schematically the layout for uti lising the method of the invention in an industrial space heater;

FIGURE 6 is a detailed schematic illustration of the operation of valve G, illustrated in FIGURE 1.

Referring to FIGURE 1 of the drawings, operation according to the invention is as follows:

A liquid fuel, such as kerosene, is contained in a container 1, to which a combustible gas, such as propane, is fed at 2 from a container 3 the gas in the container being under pressure and preferably in the liquid state.

A by-pass line 4 for providing the gas to the burner of the heater is provided. The liquid fuel is supplied to the burner through line 5. Valves, taps, or the equivalent denoted y F, G are provided for control purposes in the supply lines of the combustible gas and of the liquid fuel.

In operation a supply of combustible gas through line 4 is first turned on and ignited at the burner and the supply maintained until the burner head of the heater reaches the required temperature for ignition of the liquid fuel.

The line 5 is then opened to supply liquid fuel to the burner and the line 4 is wholly or partially closed depending on operational requirements.

The supply of liquid fuel to the burner is maintained by pressure at 2 of the gas in container 3 on the liqiud in container 1.

To prevent flame failure at the burner thermostatic control means which may comprise a flame control valve, a magnetic valve or solenoid indicated schematically and denoted G in FIGURES 1 and 6 of the drawings operates automatically as and when required to ensure a flow of combustible gas sufiicient to maintain the flame of the liquid fuel at the burner.

The valve illustrated schematically and denoted D in the drawings is provided to ensure that at the end of combustion if the liquid fuel in the supply line or in the burner is not exhausted the supply of liquid fuel from 1 may be turned off at valve E and by closing valves A and C gas from 3 may be directed through the liquid fuel line 5 to flush the line and burner and purge the burner of carbon or other products of combustion which 7 may have accumulated during combustion.

In the burner illustrated in FIGURES 3 and 4 gas is first fed through line 4 to a gas jet 7 and ignited, combustion being continued until the liquid fuel jet 8 is heated sufficiently to ensure combustion of the liquid fuel which is forced through line 5 and coil 6 by pressure of the gas at 2 on the liquid fuel in 1, the valve A being opened to permit this pressurising of the liquid fuel supply.

After ignition of the liquid fuel at jet 8 the supply of combustible gas may either be turned off, reduced, or switched to pilot control as required.

The flame from the liquid fuel jet 8 is directed by means of the stabiliser 9 which is so disposed that the flame is concentrated and controlled and heat from the burner head is directed at an inclination on to the burner coils to ensure maximum heating of the burner coil. The stabiliser is disposed substantially in line with the flame issuing from the jet but at an inclination to the direction of the flame as indicated in FIGURE 3.

In the burner shown in FIGURE 4 gas is fed through line 4 to gas jet 7, where it is ignited to effect pre-heating of the burner 8. When the liquid fuel jet is sufliciently heated to ensure ignition and combustion of the liquid fuel, line 5 is opened and the liquid fuel is led through tube 10, space 11, and tube 12 to the jet 8 where it is ignited, the flame being directed and concentrated by means of a stabiliser disposed as hereinbefore described in relation to the flame.

It will be appreciated that in both constructions of burner the liquid fuel is heated as it passes to the burner nozzle and that improved combustion is thereby effected.

A draught regulator plate, not shown in the drawings, adapted to be movable along the burner feed lines and to be clamped in a determined position, may be provided so that the flow of air to the burner may be varied as required.

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FIGURE 5 illustrates schematically the operation of the method and means according to the invention in a space heater.

In the drawing, 13 denotes a burner or burners as hereinbefore described, mounted in a combustion chamber 14 of cylindrical form with a closed conically shaped end and mounted in a container 15. Part 16 of the combustion chamber may be formed of perforated sheeting. Fan means denoted by 17 in the diagram may be utilised to increase the dispersion of the heat from the combustion chamber 1. The burners are pre-heated by a combustible gas and operate on a liquid fuel pressurised by the gas as hereinbefore described to heat the chamber 14.

The heat from the burners on passing along the chamber 14 to the closed end is forced outwardly and passes through the perforations of part 16 and in so doing causes the temperature of the perforated part to rise to incandescence and to radiate heat into the annular space surrounding the combustion chamber. Heat transfer is therefore effected both by convection and by radiation.

What is claimed is:

1. A heater, comprising: a liquid fuel burner jet, a liquid fuel supply line connected to said liquid fuel burner jet, a combustible gas burner jet, a combustible gas supply line connected to said combustible gas burner jet, said combustible gas burner jet being mounted in close, spaced relationship to said liquid fuel burner jet whereby upon ignition of said combustible gas burner jet the flame issuing therefrom pro-heats said liquid fuel burner jet to permit ignition of the liquid fuel supplied thereto, said liquid fuel supply line including a closed circuit member disposed forwardly of said liquid fuel burner jet, whereby upon ignition of said liquid fuel burner jet the flame issuing therefrom pre-heats said liquid fuel, and guide means for stabilizing and directing said liquid fuel flame toward said closed circuit member.

2. A heater as claimed in claim 1 wherein said closed circuit member comprises a coil member having a plurality of turns, said coil member being spaced from said liquid fuel flame and in concentric relationship thereto.

3. A heat-er as claimed in claim 1 wherein said closed circuit member includes a flat head substantially perpendicular to said liquid fuel flame and positioned in spaced alignment therewith, said head having a passage therein through which said liquid fuel passes.

4. A heater as claimed in claim 2 wherein said guide means comprises a tubular member disposed in the line of said liquid fuel flame, said tubular member having its axis offset from the axis of said flame, whereby said flame is directed toward said coil member.

References Cited by the Examiner UNITED STATES PATENTS 316,385 4/1885 Myers et a1 158-60 X 954,380 4/1910 Davis 158-79 1,480,848 1/1924 Walsh l58'79 X 2,111,239 3/1938 Elze 158-60 2,819,758 1/1958 Nagel. 3,097,687 7/1963 Fannin 15879 FREDERICK L. MATTESON, JR., Primary Examiner.

ROBERT A. DUA, Examiner. 

1. A HEATER, COMPRISING: A LIQUID FUEL BURNER JET, A LIQUID FUEL SUPPLY LINE CONNECTED TO SAID LIQUID FUEL BURNER JET, A COMBUSTIBLE GAS BURNER JET, A COMBUSTIBLE GAS SUPPLY LINE CONNECTED TO SAID COMBUSTIBLE GAS BURNER JET, SAID COMBUSTIBLE GAS BURNER JET BEING MOUNTED IN CLOSE, SPACED RELATIONSHIP TO SAID LIQUID FUEL BURNER JET WHEREBY UPON IGNITION OF SAID COMBUSTIBLE GAS BURNER JET THE FLAME ISSUING THEREFORM PRE-HEATS SAID LIQUID FUEL BURNER JET TO PERMIT IGNITION OF THE LIQUID FUEL SUPPLIED THERETO, SAID LIQUID FUEL SUPPLY LINE INCLUDING A CLOSED CIRCUIT MEMBER DISPOSED FORWARDLY OF SAID LIQUID FUEL BURNER JET, WHEREBY UPON IGNITION OF SAID LIQUID FUEL BURNER JET THE FLAME 